Mobile terminals such as smartphones are expected to be thinner and lighter in weight these days. Since the thickness of a smartphone is determined mainly by the height of the camera module that is mounted in the smartphone to capture images (perform imaging), there is a demand for reductions in the heights of such camera modules.
In response to the demand for reductions in the heights of such camera modules, thinner components for camera modules are being developed.
Meanwhile, a mounting method for electrically connecting an imaging element (an image sensor) that captures images to the outside of a camera module may be wire bonding or flip-chip mounting, for example.
By wire bonding, however, a camera module becomes larger in size. Therefore, flip-chip mounting, not wire bonding, is used in the mounting of an imaging element (see Patent Document 1, for example).
Meanwhile, as the components for camera modules have become thinner, the strengths of the components have become lower. Particularly, the proximity components to be brought close to the imaging elements in camera modules have become thinner, and have lower strengths.
Therefore, when a smartphone or the like having a camera module mounted therein falls and is subjected to impact, for example, the proximity components will be deformed and come into contact with the imaging element. In such a case, the risk of cracking (breakage) of the imaging element is higher.
To counter this, a technique has been suggested so that a space between an imaging element and a back-surface-side member provided on an optical back surface on the opposite side of the imaging element from the light receiving surface is filled with a joining material for joining the imaging element to the back-surface-side member (see Patent Document 2, for example).